1. Technical Field
The present invention relates to an apparatus for damping relative movement between parts, and is particularly directed to a rotary shock absorber for use in a vehicle suspension system.
2. Background Art
A multitude of shock absorbers for use in a vehicle suspension system are known. Some shock absorbers include a piston which axially moves within a cylinder. Such a shock absorber may define the minimum height of the vehicle hood or may minimize the passenger compartment size or trunk size. As known for today's automobiles, it is desirable to minimize the height of the vehicle hood for improved aerodynamics and for providing a relatively large trunk and passenger compartment.
Some shock absorbers are of the rotary type in which a rotatable member is angularly movable relative to a nonrotatable member. A known rotary shock absorber for use in a vehicle suspension system is disclosed in U.S. Pat. No. 4,503,952. The rotary shock absorber of U.S. Pat. No. 4,503,952 includes a nonrotatable member and a rotatable member defining a plurality of shear gaps therebetween. Each of the shear gaps contains a viscous fluid dispersion. Upon relative angular movement between the rotatable and nonrotatable members, the resistance to shear of the viscous fluid dispersion in the shear gaps damps movement of the rotatable member relative to the nonrotatable member.